Geothermal
nuclear
hydro electric power
California's position on the Pacific Plate boundary makes it rich in geothermal energy resources. The tectonic activity in the region, including hot springs and volcanic activity, creates ideal conditions for harnessing geothermal energy. This renewable energy source is abundant and sustainable, offering a significant opportunity for California to meet its energy needs while reducing carbon emissions.
Geothermal energy is most likely to be abundant in California due to its position on a plate boundary, specifically the San Andreas Fault. The geothermal activity associated with the fault system provides a significant potential for harnessing heat energy from the Earth's crust. This renewable energy source can be used to generate electricity and heat buildings in the region.
Now Romania hasn't an abundant source of energy.
Romania has energy resources but not so abundant.
A mountainous region would likely be a good source for hydropower energy due to abundant flowing water that can be harnessed for hydroelectric power generation.
Solar.
The sun
Solar.
Coal is the most abundant in the USA
The people in Russia do have an abundant energy source. Russia is a world leader in the production of renewable energy, mainly through hydroelectric power sources.