Blogs

Cost of Solar PV + Storage in Kauai, Hawaii

In Kauai island of Hawaii, AES is installing 28 MW of solar PV with 20 MW/100 MWh of battery for $0.11/kWh.  In 2015, 13 MW solar PV with 52 MWh battery from SolarCity was signed for $0.145/kWh.  With significant storage, this was billed the "first fully dispatchable solar plant."

Currently the island is powered by diesel and the generation cost is 0.15+ per kWh.  The average residential tariff is $0.323/kWh.  And no discussion is complete without the beautiful duck curve:

If KIUC could move some of it solar generation to later hours, it could decrease its reliance on dirty fuel oil, prevent solar curtailment at midday, and save customers money.  
 
 
 

PV Plants Providing Frequency Response Services

We have always wondered if RE plants can provide frequency and voltage support to the grid,  First Solar is making the case:

"First Solar slightly curtailed power output at a 300-megawatt solar farm in California, enabled its array of inverters, and plugged into CAISO’s system. It then orchestrated the plant’s output to follow CAISO’s automatic generation control (AGC) signals, respond to its frequency regulation commands, and use inverters for voltage regulation, power factor regulation and reactive power control."

For more details see https://www.greentechmedia.com/articles/read/PV-Plants-Can-Rival-Frequen...

First US Offshore Wind Farm Starts Delivering Electricity

Yesterday, the Block Island wind farm off the coast of Rhode Island was commissioned and started powering homes in the island. It is a 30 MW wind farm with five turbines, but one of the turbines is not yet operating.

In other development, yesterday Shell won a Dutch auction for offshore wind energy (22 Km from shore) at 0.05450 Euros per kWh, that is less than $0.06 per kWh. The previous auction in July this year was won by Dong at 0.0727 Euros per kWh. These exclude transmission costs.

Earlier this year Vattenfall won a bid at 0.0499 Euros for 600 MW Kreigers Flak offshore wind project in Denmark.

At this rate, offshore wind may be already cost competitive with new fossil-fuel plants in these European countries .

Falling Cost of Operations and Maintenance (O&M) and Longer Service Contracts

Gone are the days when turbine manufacturers were reticent to offer more than 3 to 5 years of bumper-to-bumper service contracts. Now we are seeing 15-year full service contracts. This is huge for developers because it reduces uncertainty of both energy production and O&M cost, thereby increasing financeability of a project. In addition, the cost of O&M has fallen 30% in the last 5 years. For more see, http://analysis.windenergyupdate.com/operations-maintenance/turbine-supp....

With lower PPAs and feed-in tariffs, the push is towards lower and more predictable O&M costs. With data analytics and more efficient supply chains, it is predicted that the costs will fall 20% in the next five years. See http://analysis.windenergyupdate.com/content/wind-om-dallas-2016-keynote....

Hybrid--Wind, Solar, Energy Storage and Diesel

Gamesa has installed a 2 MW prototype hybrid system with 850 kW of wind, 245 kW of solar PV, 3x222 of diesel genset and 429-kilowatt/500-kilowatt-hour of lithium-ion. This cuts the cost of electricity by 40% compared to diesel alone, however cost details of this installation are not available.  For more details see https://www.greentechmedia.com/articles/read/gamesa-targets-40-percent-s...

Performance of US wind farms

LBNL reported the following comparative performance numbers for wind turbines.  The comparison is between 1998-99 and 2015:

- Average capacity of WTG has increased by 180%

- Average hub height has increased by 47%

- Average rotor diameter has increased by 113%

As a result of these, the capacity factor of WTGs has increased from 26% to 41%.

In 2015, the average prices of wind projects had fallen to $1,690/kW (which is 20% to 40% below 2008 prices)

With these efficiencies and cost reductions, PPA for wind projects in US are averaging about $0.02/kWh in 2015.

4 hour energy storage flywheel

I thought I would never see a flywheel with 4 hours of energy storage.  Amber Kinetics has managed to develop a 6.25 kW flywheel with 29 kWh of energy storage.  The traditional flywheels I was aware of stored less than one minute of energy.

Here is what we know:

- Weight of flywheel = 5,000 lbs

- Speed of rotation = 8500 rpm

- Flywheel is a monolithic steel rotor

- Flywheel is also used as rotor for the motor/generator

- Stator is 8 pole permanent magnet

- Full power conversion to get 60 Hz AC

Although no cost is mentioned, one of their key objectives is low $/kWh cost and second is low self discharge rate.

Details are available at: http://www.energy.ca.gov/2015publications/CEC-500-2015-089/CEC-500-2015-...

Hawaii Electric seems to be the first customer.