1. Compressed Air Energy Storage
1.1. Providing external storage system for wind power plants that stores excess energy
1.2. alternate idea: "Solar Bank" to provide storage for households that generates solar energy.
1.2.1. can go off-grid if efficient enough.
1.2.2. TESLA's project on making portable storage for households TESLA Batteries and Camouflaged Solar Panels
2. Pumped Hyrdroelectricity
2.1. During peak hours, release stored water through turbine. During low demands, upper reservoirs is recharged using low-cost electricity from the grid to pump water back up.
3. Sources: https://www.greentechmedia.com/articles/read/the-long-term-storage-challenge-batteries-not-included http://reneweconomy.com.au/the-new-thinking-in-energy-storage-creating-a-solar-bank-57928/ http://www.itm-power.com/sectors/power-to-gas-energy-storage http://www.itm-power.com/project/thuga-power-to-gas http://www.itm-power.com/news-item/thuga-power-to-gas-project-update http://www.tepco.co.jp/en/forecast/html/dounaru2-e.html http://www.sciencedirect.com/science/article/pii/S0960148115301610 http://energystorage.org/energy-storage/technologies/pumped-hydroelectric-storage https://www.wired.com/2016/10/tesla-unveils-new-line-camouflaged-solar-panels/ https://www.wired.com/2015/05/teslas-batteries-will-power-home/
4. Introduction/ Defining the problem: How TEPCO deals with excess output?
4.1. No excess output as they generate in proportion to demand
4.2. Electricity is cheapest when power plants can run non-stop -- it distributes the capital cost over more units of produced energy.
5. Chemical Energy Storage
5.1. Producing hydrogen + methane through electrolysis
5.1.1. input: power(excess) & water Process: H2O converted to H2 through electrolysis. Through methanation the product can output the compound CH4 (Methane) to be used in Gas grids and vehicle fuels.
5.2. hydrogen + methane can be used for other means and can be recycled back to the grid (long-term storage)
5.2.1. capable of, at the request of the transmission system operator (TSO), increasing the load of the electrolyser when too much power is on the electrical grid
5.3. THÜGA POWER-TO-GAS PROJECT
5.3.1. Outcome: Thüga reported that the system has been declared ‘technically able to participate in the secondary power market’.
5.3.1.1. electrolyser system has met every aspect of its specification including efficiency, remote control functionality and response time.