Energian tuotanto, kenttägeneraattorit ja muut


The development and research project “StEnSEA” (Stored Energy in the Sea) is investigating the installation of large storage facilities on the sea floor, in combination with offshore wind farms. The physical principle on which the energy storage facility operates is similar to that of conventional pumped storage power plants, but based not on two reservoirs, but a hollow sphere. The inflowing water drives a turbine to generate electricity. When there is a surplus of electricity in the grid, part or all of the water is pumped out of the sphere. The commercial target size per sphere is currently at about 20 MWh per storage unit.

he functional principle is similar to ordinary pumpedstorage plants: when power is needed, water flows into the sphere and drives the turbine thus generating power. If surplus power is available (usually during the night), water can be pumped out of the sphere again, thus effectively charging the storage system. This innovative concept uses the sea itself as upper reservoir.

A hollow sphere with an inner diameter of 30m will be submerged to a water depth of about 700m, so the hydrostatic water pressure creates an energy potential. Due to this applied pressure, electrical energy can be generated with the help of turbines and generators as the water flows into the sphere. A cable connection to the transformer station and from there to the mainland makes the transport of electrical energy possible. The other way around, exess energy, for example from renewable sources, can be used to pump out water from the hollow sphere. The commercial target size per sphere is currently at about 20 MWh (4 hours discharge time for a 5 MW pump turbine) per storage unit.

For the time being, the current approaches of the feasibility study are based on a maximum water depth of 700 m. This is based on the fact, that there are state-of-the-art turbines that can function in such water depths. Construction and installation would be possible in even greater water depths without problems. However, in such case a separated pump and turbine system must be used and/or the turbine technology should be further developed.


Pumped storage is a decades-old technology with a relatively simple concept: When electricity is cheap and plentiful, use it to pump water up into a reservoir above a turbine, and when electricity is scarce and expensive, send that pumped water down through a turbine to generate more power. Often, these pumped storage facilities are auxiliary to other electricity-generating systems, and they serve to smooth out fluctuations in the amount of power on the grid.

A German research institute has spent years trying to tailor pumped storage to ocean environments. Recently, the institute completed a successful four-week pilot test using a hollow concrete sphere that it placed on the bottom of Lake Constance, a body of water at the foot of the Alps. The sphere has a diameter of three meters and contains a pump and a turbine. Much like traditional pumped storage, when electricity is cheap, water can be pumped out of the sphere, and when it’s scarce, water can be let into the sphere to move the turbine and generate electricity.

The Fraunhofer Institute for Wind Energy and Energy Systems Engineering envisions spheres with inner diameters of 30m, placed 700m (or about 2,300 ft) underwater. Assuming the spheres would be fitted with existing 5 MW turbines that could function at that depth, the researchers estimate that each sphere would offer 20 MWh of storage with four hours discharge time.

In an underwater “energy park,” dozens of these spheres could be connected near an offshore wind farm to create a system that would be able to add extra reliability to a renewable-heavy grid. The institute admits that the economics of this project only work on a large scale. It estimates that more than 80 spheres would be needed “to achieve a relevant overall performance/capacity for the energy market.”

In November, the Fraunhofer Institute placed the test sphere 200m off the coast of Lake Constance and 100m under the lake’s surface. The institute just retrieved its sphere last week. Researchers are still sifting through the data gleaned by the pilot program in order to create better computer models on how this scheme would work in the real world. The institute wrote that it wants to conduct a follow-up project using a larger sphere that would be underwater for a longer time.

According to the institute’s press release, a sea-based project is still three-to-five years out, but industrial partners and public sponsors are apparently interested in financing the project further. This test was completed with help from Germany's Federal Ministry of Economics and Technology.



The Kapaia project is a combination 13MW SolarCity solar farm and 53MWh Tesla Powerpack station on the island of Kauai. In partnership with the KIUC (Kauai Island Utility Cooperative) the project will store the sun's energy during the day and release it at night. The station (along with Kauai's other renewable resource solutions including wind and biomass) won't completely keep the island from using fossil fuels but it will temper the need.


Utilities are charged with serving the public interest: They must keep the lights on. That means they need to have something in reserve for times when more electricity is needed than is usual for a given day and time or for those times when equipment is out of service. They need operating reserves, known in electric utility parlance as spinning reserves (obtaining more output from generators already operating) and non-spinning reserves (quickly bringing generators online to meet demand spikes).

Renewable generation poses several challenges to reliable operation of power systems thanks to its inherent variability: Wind speed and direction isn't a constant for example. Operating reserves compensate for variability in both load and generation.

How much does adding renewables to the grid change what operating reserves are needed and how they are dispatched during spikes of demand? That’s what our part in the Full Cost of Electricity (FCe-) project by the University of Texas at Austin Energy Institute seeks to understand.



“Batteries are complicated.” This was the unrehearsed refrain I heard repeatedly from Mike Toney and the researchers who make up the Toney research team at the Stanford Synchrotron Lightsource (SSRL), part of the SLAC National Accelerator Laboratory in Menlo Park, Calif.

During a visit to to their laboratories, I learned that not only are the complex inner workings of batteries being revealed by the assortment of X-ray microscopy tools used at SSRL, but that the latest innovations in photovoltaics are being examined and characterized with the aim of making sure that both energy storage and energy generation technologies can meet the demands of future generations.


huhtikuu 6, 2017 6:48 https://www.suomenuutiset.fi/infraaanen-vaikutuksille-virallinen-vahvistus-kuntien-laitettava-tuulivoimaloiden-rakennusluvat-jaihin-ihmisten-pinna-alkaa-loppua/
Infraäänen vaikutuksille virallinen vahvistus: Kuntien laitettava tuulivoimaloiden kaavoitus ja rakennusluvat jäihin – ”Ihmisten pinna alkaa loppua”

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Tuulivoimaloiden infraääni aiheuttaa haitallisia terveysvaikutuksia ihmisille ja eläimille eri puolilla Suomea. Näin on käynyt esimerkiksi Kurikassa Etelä-Pohjanmaalla.

Kurikan naapurikuntaan Ilmajoelle on rakennettu Santavuoren tuulivoima-alue, jossa on 17 voimalaitosta. Ne ulottuvat yli 200 metrin korkeuteen.

Kurikkalainen Päivi Peltoniemi asuu alle kymmenen kilometrin päässä Santavuoren alueesta.

– Voimaloiden toiminta käynnistyi viime keväänä ja pian sen jälkeen minulle tuli rytmihäiriöitä, korvien lukkiutumista ja päänsärkyä, Peltoniemi kertoo.

Ei oireita ennen tuulivoimalaa

Peltoniemen mukaan hänellä ei ollut oireita ennen tuulivoimaloita. Hän on havainnut, että oireet pahenevat kovalla tuulella.

– Verenpaine sahaa edestakaisin ja minua huimaa välillä. Pahimmilla tuulilla jopa lemmikkieläin lakkaa syömästä ja makaa reporankana. En tiedä pystynkö enää asumaan kotona kesällä.

Kymmenet perheet ovat joutuneet muuttamaan pois kodeistaan tuulivoimahaittojen takia.

ISO:n standardi vahvisti

Peltoniemen mukaan hänen ja lukuisten muiden ihmisten kokemat oireet johtuvat tuulivoimaloiden infraäänestä. Tuulivoimalobbarit vähättelevät ihmisten kokemuksia ja pitävät niitä keksittyinä.

Kansainvälisen standardisoimisjärjestö ISO:n standardi kuitenkin todistaa, että ihmisten tuulivoimaloiden aiheuttamiksi kokemat oireet ovat todellisia. ISO vahvisti jo vuonna 1996, että alle 1 Hz:n (hertsin) infraääni aiheuttaa ihmisille oireilua.

– Tieto on ollut olemassa, mutta se on pitänyt kaivaa esiin päivänvaloon, Peltoniemi sanoo.

Pidetty mielikuvituksen tuotteena

Tuulivoimalat tuottavat alle 1 Hz:n matalataajuista infraääntä, joka liikkuu säännöllisesti toistuvina sykäyksinä ja on ihmiskorvien ulottumattomissa. ISO 9996:1996 standardin mukaan alle hertsin infraääni aiheuttaa meritautia, matkapahoinvointia, huimausta ja ahdistuneisuutta.

– Tämä tieto on merkittävä kaikille niille ihmisille, joiden tuulivoimaloista saamia terveyshaittoja on pidetty vain mielikuvituksen tuotteena, Peltoniemi toteaa.

Terveyshaitoista iso lasku

Peltoniemi on yrittäjä ja oireilun takia työnteko on kärsinyt.

– Tämä iskee pienyrittäjiin ensimmäisenä, kun ei ole sijaisia. Suuri osa yrittäjistä työskentelee yksin ja siitä aiheutuu iso lasku kansantaloudelle, jos emme pysty tekemään töitä sairastumisen takia.

Peltoniemen mielestä kunnissa ajatellaan lyhytnäköisesti, kun tuulivoimalobbarit hehkuttavat päättäjille voimaloiden maanvuokratuottoja.

– Kunnissa ei ole ymmärrystä tuulivoimaloiden haittavaikutuksista. Nyt on noustava barrikadeille ja pantava piste tuulivoimarakentamiselle. Suomi on ihmisten sairastumisen myötä konkurssissa, jos viisaus ei löydy hallituksen riveistä, Peltoniemi sanoo.

Ihmiset ottavat päivittäin yhteyttä

Perussuomalaiset ovat nostaneet ainoana puolueena esille tuulivoimalamelusta ja infraäänestä kärsivien ihmisten asian.

– Tuulivoimaloiden haitoista kärsivät ihmiset ottavat yhteyttä päivittäin. ISO:n standardi on iso juttu. Se todistaa, mitä infraääni aiheuttaa, toteaa perussuomalaisten työmies Matti Putkonen.

Ympäristöministeriön mukaan tuulivoima-alueiden kaavoitus on tällä hetkellä hyvin aktiivista Suomessa. Tuulivoiman rakentamista pyrkii edistämään Suomen tuulivoimayhdistys, joka on tuulivoiman kotimainen edunvalvontajärjestö. Se toteaa verkkosivuillaan, että teollisen tuulivoiman rakennustilastoja tullaan rikkomaan tulevina vuosina.

Yhdistyksen mukaan viime vuonna Suomeen rakennettiin 182 uutta tuulivoimalaa, joita on yhteensä lähes 400.

Tutkimus PS:n vaatimuksesta

Hallitus aikoo teettää selvityksen tuulivoimalamelun ja -infraäänen terveyshaitoista perussuomalaisten vaatimuksesta.

– Tuulivoimayhtiöiden tulisi herätä vihdoin ja viimein. Ihmisten pinna alkaa loppua eri puolilla Suomea. Hätä on suuri, Putkonen tietää.

Putkosen mukaan perussuomalaiset ovat yrittäneet vedota tuulivoimayhtiöihin, jotta ne lopettaisivat hätää kärsivien ihmisten pilkkaamisen.

– Tällaisten yhtiöiden ei pidä saada mitään valtion tuotantotukea. Ylimielisyydellä ja ihmisten pilkkaamisella pitää olla joku raja, Putkonen jyrähtää.

Kunnilla iso rooli

Muissakin puolueissa olisi Putkosen mielestä herättävä, että oirehtivat ihmiset ovat Suomen kansalaisia, joista on pidettävä huolta.

– Vihreät, SDP, vasemmistoliitto, kokoomus ja osa keskustasta pitää tuulivoimaa uusiutuvan energian brändinä. Punavihreä energia ei ole suomalaista. On käsittämätöntä, miten yhtiöt käsittelevät ihmisiä ja hakevat veroeuroja. Ihmisille kuuluu oikeus saada tietoa, mikä heitä vaivaa ja mikä sen aiheuttaa.

Selvitys tuulivoimaan liittyvistä terveysvaikutuksista valmistuu Putkosen mukaan puolentoista vuoden kuluttua.

– Siihen asti kunnilla on iso rooli. On tärkeää, että tulisi valtuustot, jotka panisivat kaavat ja rakennusluvat jäihin selvityksen valmistumiseen asti. Ainoastaan perussuomalaisten vaaliohjelmassa tämä on mukana. Toivottavasti muut puolueet lähtisivät siihen mukaan, Putkonen esittää.



Hydrostor, the Canadian company that wants to store energy as compressed air in large balloon-like bags underwater, is now turning its attention to terra firma. Specifically, the company unveiled a system to store large-scale energy in underground compressed-air caverns.

The system comes in at “half the cost of competing battery technologies, and on part with new natural gas plants,” the company claims.

The case for storing large quantities of electrical energy is getting stronger and stronger, whether to expand the use of solar and wind power or to meet surges in demand on the grid. Batteries are making headway for energy storage, but compressed-air energy storage (CAES) is a strong contender. Such systems use off-peak electricity to run compressors and store the compressed air, which can later be expanded to drive a turbine.

CAES systems have the potential to cost less and last longer once they have been built. The problem with conventional CAES is that it is expensive and requires underground geological formations to store the air.


For the first time ever in April, the UK's data centres and clouds ran on electricity generated without burning coal.

The National Grid celebrated the news on Twitter with the promise of more coal-free days to come.

As coal-fired power plants wind down and with talk of blackouts in the air, nuclear is back on the table after the government gave the go-ahead last year for a third reactor at Hinkley Point in Somerset. Hinkley Point C is an £18bn, 35-year scheme that'll be operated by EDF. It took financial backing from the Chinese government to land.

However, a cheaper and smaller alternative is emerging if activity from British entrepreneurs and academics is anything to judge by – the small "modular" nuclear reactor, or SMR.

Mini reactors are nothing new – they have been installed in nuclear submarines since the 1950s, and Rolls-Royce produced them for the Royal Navy for decades.

An SMR is defined as producing 300MWe – just 10 per cent of what Hinkley Point C should provide.

SMRs are defined as reactor systems that are comparatively small, compact and entirely factory built. As a result, SMRs can be placed underground or underwater and moved for decommissioning. They employ "passive" safety systems that do not require human intervention – therefore fewer staff – and use a relatively small amount of nuclear material. There are a number of different SMR designs.


Suomalaistutkijat valmistavat aurinkosähköllä raakaöljyä ilmasta – Mullistava koelaitos käynnistyi Lappeenrannassa
Tutkimusryhmän mukaan Soletair-niminen koelaitos on jo herättänyt merkittävää kansainvälistä kiinnostusta.

9.6.2017 klo 14:06päivitetty 9.6.2017 klo 14:16 https://yle.fi/uutiset/3-9652845


Sähkön varastointi voi olla yllättävä käänne. Varsinkin ne on yleensä laitettu näiden uusiutuvien energianmuotojen yhteyteen.

The Analysis Group report concludes many advanced energy technologies such as efficient natural gas-fired generation and renewables provide reliability benefits by increasing the diversity of the electric system. As wind and solar energy become more prominent in certain regions, the trend in reliability performance in these areas is increasing rather than decreasing, the report says.


40 kW fissiogeneraattori Marsin yhdyskunnalle.

As NASA makes plans to one day send humans to Mars, one of the key technical gaps the agency is working to fill is how to provide enough power on the Red Planet’s surface for fuel production, habitats and other equipment. One option: small nuclear fission reactors, which work by splitting uranium atoms to generate heat, which is then converted into electric power.

NASA’s technology development branch has been funding a project called Kilopower for three years, with the aim of demonstrating the system at the Nevada National Security Site near Las Vegas. Testing is due to start in September and end in January 2018.


This week, through a competitive bidding process, Tesla was selected to provide a 100 MW/129 MWh Powerpack system to be paired with global renewable energy provider Neoen’s Hornsdale Wind Farm near Jamestown, South Australia. Tesla was awarded the entire energy storage system component of the project.

Tesla Powerpack will charge using renewable energy from the Hornsdale Wind Farm and then deliver electricity during peak hours to help maintain the reliable operation of South Australia’s electrical infrastructure. The Tesla Powerpack system will further transform the state’s movement towards renewable energy and see an advancement of a resilient and modern grid.

Upon completion by December 2017, this system will be the largest lithium-ion battery storage project in the world and will provide enough power for more than 30,000 homes, approximately equal to the amount of homes that lost power during the blackout period.


Aurinkosähkön käyttö yleistyy, mikä tuo uusia haasteita pelastusviranomaisille. Isojen kiinteistöjen katoilla olevat aurinkopaneelit ovat tulipalossa palomiehille turvallisuusriski.

– Sähköön liittyy yleensä aina työturvallisuusriski pelastushenkilöstöllä. Aurinkosähköjärjestelmissä on se ongelma, ettemme tiedä, missä sähkö kulkee. Sitä ei välttämättä saada katkaistua aurinkopaneeleista, selittää ruiskumestari Vesa Läderberg Päijät-Hämeen pelastuslaitokselta.

Aurinkopaneeleissa kulkee valoisaan aikaan aina jännite. Läderbergin mukaan jännite vaikeuttaa rakenteiden purkamista palotilanteessa ja vaatii tarkkuutta vedellä sammuttaessa.

Ongelmaan ollaan vasta havahtumassa. Pelastushenkilöstön turvallisuusohjeet aurinkosähköjärjestelmien kohdalla ovat vielä kansainvälisestikin työn alla.

– Kansainvälinen järjestömme on vasta käynnistänyt turvallisuusohjeiden suunnittelun. Syksyllä julkaistavaaan uuteen asennusstandardiin on tulossa tarkennuksia koskien myös aurinkopaneeleja ja ylivirtasuojauksia, sanoo turvallisuusasiantuntija Lauri Lehto Suomen Pelastustusalan Keskusjärjestöstä.

Lehto muistuttaa, että aurinkopaneelien asennukset pitää toteuttaa säännösten mukaan ja esimerkiksi huolehtia kaapelointien suojauksesta.



1800 MW vesivoimala kuulemma tässä kuvassa

The station itself is almost entirely underground, it lies inside the Snowdonia (Eryri in Welsh) National Park, and thus its construction was required to impose minimal visual impact. The Dinorwig slate quarry is an abandoned industrial site on the slopes of Mynydd Elidir Fawr, and the power station itself sits almost entirely inside the mountain with only some unobtrusive structures on the surface at the bottom of the quarry’s terraces. Besides this, the other parts that are visible are the upper reservoir, the mountain top lake Marchlyn Mawr, a surge pond at the top of the high pressure downward shaft, and the lower reservoir, another lake, Llyn Peris.

Beneath the surface, there are 16 km (about 10 mi) of tunnels in the complex, and some of the largest man-made underground caverns in the Europe containing the valve gear, turbine and generator assemblies, and transformers. And when we say tunnels it is important to understand that these are not stoop-unless-you-are-a-hobbit sized tunnels, but huge brightly-lit tunnels containing full-size roads, large enough for specialist haulage trucks to have delivered monster-sized power station transformers and other machinery into the middle of the mountain. The tour bus is an ordinary road vehicle, looks small in the tunnels. The rock from which they are cut is the same slate that originally brought the quarrymen to Dinorwig, we are told that since it is a brittle material all the surfaces have been given a spray concrete treatment.
The generators produce 18 kV AC at the UK line frequency of 60 Hz synchronised to the grid. This is converted through a transformer to the grid transmission voltage of 400 kV, then sent through an underground transmission line to a substation a few miles away. Dinorwig’s very fast start-up time is achieved by keeping some turbines constantly spinning in compressed air using power from the grid, in this way they avoid the extra wait to spin up the very heavy shafts to operating speed when the valve is opened. The station also has a set of diesel generators to allow the turbines to be spun up in the event of there being no grid power, this would allow it to be used to restart the UK grid in the event of a complete power loss.
Ei kuitenkaan energia säilötä taikka sen talteenottoa ja myöhempää sääntelyä valuman ollessa normitasalla.


Google and Tri Alpha Energy, a Californian energy company, say they have come up with an algorithm that appears to help scientists generate hotter plasma more efficiently for nuclear fusion experiments. Keyword: experiments.

Billions of dollars have been poured into achieving clean, carbon-free energy harnessed from smashing atoms together. Yet progress has been slow. It’s tricky, as well as massively expensive, to sustain a hot plasma environment necessary for fusion reactions.

Enter the Optometrist Algorithm. This code is designed to produce this vital plasma more efficiently. The amount of energy required to fire up and operate today's fusion systems would vastly outweigh whatever useful energy you can get out of them. The algorithm attempts to help boffins close that gap and thus steer the technology toward being an economically viable electrical power source – a replacement for coal, gas and nuclear fission, in other words.


40 MW energiasäilö. Ei ole monessa paikkaa tuollaisia.

Massachusetts might be getting a massive new wind farm that uses Tesla batteries to store energy.

Deepwater Wind, a wind energy development company, has proposed a 144-megawatt wind farm with 40-megawatt hours of battery storage for a site 30 miles from mainland Massachusetts and 12 miles south of Martha’s Vineyard, the company announced Tuesday.


A Dutch nuclear research institute has just fired up the first experiment in nearly half a century on next-generation molten-salt nuclear reactors based on thorium.

Thorium has long held promise for “safer” nuclear power. A slightly radioactive element, it transforms into fissionable U-233 when hit by high-energy neutrons. But after use, U-233 creates fewer long-lived radioactive waste products than the conventional U-235 now used in nuclear power plants.

But because nuclear power was traditionally tied up with nuclear weapons research into uranium and plutonium, thorium was mostly abandoned. Except for one test reactor that has been under construction at Kalpakkam since 2004, thorium reactor research has been moribund.

But now, NRG, a nuclear research facility in Petten, on the North Sea coast of the Netherlands, has launched the Salt Irradiation Experiment (SALIENT) in collaboration with the EU Commission. The researchers want to use thorium as a fuel for a molten salt reactor, one of the next-generation designs for nuclear power in which both the reactor coolant, and the fuel itself, are a mixture of hot, molten salt.

Many believe that molten salt reactors are well suited for using thorium as a fuel. Their unique working fluid can achieve very high temperatures, significantly boosting the efficiency of the power generation process.

The Petten team will use the facility’s reactor to melt a sample of thorium fuel and then bombard it with neutrons to transmute the thorium into U-233, which can sustain the chain reaction needed to generate energy.

A later step is to study tough, temperature-resistant metal alloys and other materials that can survive the high heat and corrosive conditions inside a molten-salt reactor. Eventually, they’ll need to examine how to deal with the waste from a molten salt thorium reactor. While largely considered safer than the long-lived products from a standard nuke, these will still need special disposal.

If this project bears fruit, there are many interests waiting to join the thorium club. A US startup based in Utah says it’s developing a thorium reactor, while a consortium of eastern Utah counties is exploring whether to participate in the project. Last month, Utah’s Seven County Infrastructure Coalition said it is searching for experts qualified to evaluate “a thorium energy facility for producing electricity”.

So is thorium power really back on the table? We’ll know by the end of the year, if the planned Kalpakkam test reactor in India starts generating energy. We will need clean energy sources to stave off climate change, yet fears raised by the Fukushima disaster have caused nuclear power to stagnate. If thorium’s long promise pays off, it’s not a moment too soon.




As the U.S. military increases its use of drones in surveillance and combat overseas, the danger posed by a threat back at home grows. Many drone flights are piloted by soldiers located in the U.S., even when the drones are flying over Yemen or Iraq or Syria. Those pilots and their control systems depend on the American electricity grid – large, complex, interconnected and very vulnerable to attack.

Without electricity from civilian power plants, the most advanced military in world history could be crippled. The U.S. Department of Energy has begged for new authority to defend against weaknesses in the grid in a nearly 500-page comprehensive study issued in January 2017 warning that it’s only a matter of time before the grid fails, due to disaster or attack. A new study by a team I led reveals the three ways American military bases’ electrical power sources are threatened, and shows how the U.S. military could take advantage of solar power to significantly improve national security.



A vast source of renewable energy has been sitting under our noses. Evaporating water could supply enormous volumes of clean electricity, if we can only harness it.

Evaporation is the process by which liquids turn into gases, generally when they are heated up. Every day, vast amounts of water evaporate from lakes and rivers, powered by heat energy from the sun. The scale of this energy is considerable.

Water that evaporates from existing lakes and dams in the US – excluding the Great Lakes – could provide up to 2.85 million megawatt hours of electricity per year, according to Ozgur Sahin of Columbia University and colleagues. That is the equivalent of two-thirds of US electricity generation in 2015. In 15 of the 47 US states studied, the potential power exceeds demand.

Covering freshwater bodies with engines that harness evaporation would halve water lost in this way, the team says. In seven US states, this would save more water than the entire state consumes. But the calculations assume that all the water is covered – which we would not want to do.

Evaporation engines could also be put in other areas, from irrigated fields and greenhouses to sheltered bays, says Sahin.

But first an evaporation engine needs to be built. Sahin’s team has created several miniature prototypes.

The prototypes are all based on materials that shrink as they dry, such as tape coated with bacterial spores. The spores curl as they dry, shortening the tape. “They work like a muscle,” says Sahin. “They can push and pull with a lot of force.”

To avoid being repeatedly soaked in water and becoming contaminated with dirt and chemicals, the prototypes exploit changes in humidity.

In one version, the “muscle” sits just above the water. When shutters above it are closed, the humidity rises and the material expands. That opens the shutters, allowing the material to dry out and shrink, and so on.

Such evaporation engines can run at night as well as day. Normally, there would be less evaporation at night, but blocking evaporation during the day stores energy in the form of warm water. “At night you take advantage of this power,” says Sahin. “This is a great advantage.”