Ripasso Energy concentrated solar power focuses the heat of the sun to highly efficient, zero-emissions Stirling engines. A test site in the Kalahari desert has reliably produced energy for four years and achieved a world record solar-to-grid electricity conversion of 32% and, big added bonus, uses no water, a major concern in deserts. By contrast, traditional solar PV has achieved about 15% usable grid power, while other forms of concentrated solar use water to power steam turbines.
The technology works by using the mirrors as giant lenses that focus the sun’s energy to a tiny hot point, which in turn drives a zero-emission Stirling engine.
The Stirling engine was developed by Reverend Robert Stirling in Edinburgh in 1816 as an alternative to the steam engine. It uses alternate heating and cooling of an enclosed gas to drive pistons, which turn a flywheel.
Ripasso says competing with the ever-dropping costs of solar PV is crucial. Their biggest challenge was getting funding from skeptical banks, so they secured private funding instead. Solar power like this would be an ideal way to power desalination plants on the coasts in deserts, as well as homes.
Concentrating solar power creates electricity by using the heat of the sun. The heat generally is focused to a central tower or stored in tubes next to parabolic troughs, then used to power turbines, creating electricity. Solar PV is way cheaper than CSP. However CSP has a huge advantage that makes it competitive. Excess heat can be stored in molten salt, then used to generate power when the sun isn’t shining or at night. Specifically, CSP can be used as backup power for solar PV when the sun is setting and demand is generally at its highest.
A ginormous CSP plant in Tunisia will generate 2.5 GW, equal to that big coal and nuclear power plants, when built and send the power to Britain via high-voltage DC cable. The builders say the cost will be competitive although Bloomberg New Energy disagrees.
Contrary to Nur Energie’s estimations, Bloomberg New Energy Finance calculates that most solar thermal plants would need a power-purchase agreement in excess of $200 per megawatt-hour to be commercially viable.
This compares to just under $100 per megawatt-hour for PV “in a similar sunny location,” Chase said. “The only reason anyone would give you that premium is if you were supplying power that matched the demand of the grid you were feeding into better than PV does.”
And that is exactly what CSP does, it provides large amounts of power precisely at the time when solar PV can no longer do so. And this is the only reason it remains viable competition.
This is particularly the case in markets such as South Africa, where there is a need to meet evening demand peaks that PV cannot handle. South African regulators have approved at least half a dozen CSP plants with storage.
BLS explains how CSP works.
Although there are several different CSP technologies, they all involve reflecting sunlight onto a focal point that contains a heat-transfer material. The heat-transfer material, usually synthetic oil or molten salt, is collected in a heat storage unit and eventually used to create steam that powers conventional generators. One advantage of CSP is that at night or on extremely cloudy days, the conventional generators can be run on natural gas or petroleum, allowing the plant to continue to generate power when the sun is not shining.
That’s right. CSP is not completely renewable. The turbines can run off carbon fuel too. However, they are still way greener that say, a coal plant.
Elon Musk is a master of PR and hype. You’d think from recent gush of laudatory, uncritical re-written press releases masquerading as journalism that Tesla Energy is doing something new by introducing home batteries. It’s not.
Home battery storage systems have been around for years. Dozens of companies sell them. They are already being used to store rooftop solar PV power, so that’s not a new Tesla idea either.
Rooftop solar with stored power in batteries is a great idea. Just don’t believe the hype and get carried away thinking Tesla is doing something no one else has. This technology has been around for a while. Tesla is the new kid on the block.
Oil and gas wells use large amounts of water, and it’s often boiling hot when it comes back up the pipes. So the oil patch is experimenting with sending that hot water through geothermal heat pumps to create electricity, to be used onsite or sold into the grid. Yes, this is mostly about using about dirty, nasty fracking water but, hey, might as well create clean energy with that water too. With the dropping price of oil, oil companies are looking for ways to make extra income per well.
The team took off-the-shelf geothermal generators and hooked them to pipes carrying boiling waste water. They’re set to flip the switch any day. When they do, large pumps will drive the steaming water through the generators housed in 40-foot (12- meter) containers, producing electricity that could either be used on site or hooked up to power lines and sold to the electricity grid.
Water heaters use large amounts of energy. The ability to them control remotely could save substantial amounts of power and money. Congress just passed a law permitting this to be done on a large-scale. Thus, on a hot day, the utility might cut power going to hot water heaters to enable that power to be used for air conditioning demand. Conversely, water heaters could be turned on if there is a temporary oversupply of power. All this happens very quickly in response to supply and demand. The switching back and forth can happen in seconds, or just a few minutes, not long enough to seriously impact available hot water since it only controls some of the power, as shown in the image.
It’s not just utilities that are using water heaters for capacity demand response which are celebrating. Hot water heaters are also increasingly being tested as grid-balancing assets. In Hawaii, water heaters are being tested for frequency regulation and contingency reserves, while in the Pacific Northwest they are being tested to balance wind resources in five-minute intervals.
Here’s how it works.
Grid-interactive water heaters add bidirectional control to electric resistance water heaters, allowing a utility or third-party aggregator to rapidly toggle them off and on. This functionality turns a fleet of water heaters into a flexible energy-storage medium, capable of increasing and decreasing the load on the grid on a second-by-second basis.
GIWHs can’t supply electricity, but they provide exactly the same functionality by reversing this equation: They can modulate the load in order to follow generation. In times of overgeneration, fleets of water heaters can be switched on to absorb excess power, and in times of undergeneration, they can be switched off to shed load and redistribute the existing electricity on the grid. Thus, aggregated GIWHs can act as virtual power plants to quickly and effectively control the amount of power on the grid. Moreover, these fleets are completely scalable and can perform this functionality within seconds.
The Carlsbad Desalination Project will be the biggest desal plant in the western hemisphere when it open in November in San Diego. While the price of desalination is dropping, it is still quite expensive and is problematic in two ways. 1) The salt is dumped back into the ocean, adversely affecting marine life. 2) Desal requires large amounts of electricity, which mostly comes from non-renewable sources now, increasing carbon emissions. Also electricity generation often requires substantial amounts of water for cooling. Thus, water is used to generated energy which is used to desalinate water. Hmm.
Renewable energy from wind and PV solar uses practically no water and could be a long-term solution to the interconnected problem of the relationship between water and electricity creation.
The project will generate 50 million gallons of water a day, enough for 7% of San Diego and will cost about $1 billion.
“Desalinated water will be more expensive than imported water when it comes online,” Jones said. “But soon, imported water rates will continue to rise and imported water will be more expensive than desalinated water. And what we need to look at as consumers is what is the cost of not having water at all.”
Paying to offset emissions elsewhere for damage the plant will do is not sustainable or a solution.
The company developing the plant here, Poseidon Water, has promised to counter the environmental damage. For instance, it will pay into a California program that finances projects to offset emissions of greenhouse gases.
I’ve said for years the best way to get renewable energy is stop emphasizing climate change. A study by Yale researchers confirms this. Even in areas of the country where most don’t think climate change is due to humans, they still overwhelmingly support R&D into renewable energy.
This is probably because there are so many other reasons to support renewables. In many areas, renewable energy already is the same cost or less than fossil-fuel generation. Renewable energy can be created nearby, cutting down on transmission costs, making electricity cheaper. Plus, having electricity come from multiple sources (as in rooftop solar everywhere) not just a few big plants, makes the grid more resilient and stronger. Otherwise vacant land can be used for wind and solar farms, generating income for owners. Texas has more wind power than any other state, and plenty of ranchers make good income leasing their land.
So maybe lecturing climate change deniers isn’t the best of all possible approaches. Instead, emphasize how renewable energy can help them – because they probably already know it!
Total worldwide wind power capacity is now 370 GW. 50 GW was installed in 2014. China led the way with 23 GW of new wind power, and has 31% of total world wind power, followed by the US at 18%. China is, uh, blowing past us.
These totals are from the comprehensive Global Wind Report for 2014 from the Global Wind Energy Council (PDF).
2014 was a great year for the wind industry, setting a new record of more than 51 GW installed in a single year, bringing the global total close to 370 GW. We knew there would be a substantial recovery last year, but nobody predicted that China would install 23 GW of new wind power alone (another record). Elsewhere in Asia, India had an unspectacular year, but we expect great things from India in the coming 5-10 years as the new government’s renewables push gets underway; and there were significant new installations in Pakistan and the Philippines, helping Asia to once again lead all regional markets and pass Europe in terms of cumulative installed capacity
Google X will soon be testing a 84-foot version of their Makani airborne wind turbine. It flies at 1,500 feet altitude, where wind speeds are much faster, and is tethered to the ground. Wind at altitude is also considerably more variable than on the ground, especially where the test will be, and Google says they want a few crashes so they can determine just how far the devices can be pushed. Each one can generate a not insubstantial 600kW.
The energy kite simulates the tip of a wind turbine blade, which is the part of a turbine that makes most of the energy. The kite is launched from the ground station by the rotors, which act like propellers on a helicopter. Once in the air, the kite generates power by flying in large circles where the wind is strong and consistent. Air moving across rotors mounted on the kite forces them to rotate, driving a generator to produce electricity, which travels down the tether to the grid.
Electricity is expensive in Philippines, compounded by growing shortages. The government has responded by leasing more power, paying big customers to generate their own power (probably by diesel), yet these seem stopgap measures. With so many islands, distributed energy via rooftop solar could help substantially.
The power profile of the three major island groups is quite different. Visayas and Mindanao get half their power from renewable sources, geothermal and hydro respectively, while Luzon relies heavily on coal. Yet new growth for all three will mainly be coal. (Big hydro is controversial, some think big dams are so damaging they shouldn’t be classified as renewable. Yet, the power does indeed come from a non-carbon source.)
The three main island regions of Luzon, Visayas, and Mindanao each have distinct generation profiles. In the northern part of the country, Luzon’s capacity is mainly powered by fossil fuels, with anticipated capacity additions of more than 500 MW, most of which will be coal-fired. Visayas, in central Philippines, currently relies heavily on its geothermal resources, but has plans to add 300 MW of coal capacity by 2017. In the south, Mindanao relies heavily on its hydropower resources, with plans for both additional hydropower capacity and additional coal-fired generation to increase system reliability.
Their Secretary of Energy says rooftop solar actually cheaper than coal.
“As a simple example, the cost of electricity from a coal plant can run up to P5.50 per kilowatt hour, plus P6.50 for distribution and transmission, which amounts to P12.00. If you install solar panels on your rooftop, you will only spend P9.00 per kilowatt hour for generation and no cost for distribution or transmission. This already saves you up to P3 per kilowatt hour.”
Let’s hope Philippines makes a big push towards rooftop solar.