In the United States, 0.005 percent of all energy consumed comes from solar. This may seem like a drop in the ocean, but it’s quite substantial. Globally, there was a 33 percent increase in global solar power generation from 2014 to 2015. Currently, the total photovoltaic (PV) power generation capacity around the world stands at 231 gigawatts. The compound annual growth rate of solar power generation in the United States is 60 percent. When it comes to energy storage, the total energy storage market in the United States is expected to be 858 MW by 2019. The solar industry employs hundreds of thousands of people in the United States. The number of people working in the industry is expected to grow from 209,000 to 360,000 by 2021, which is great for green energy enthusiasts.
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One of the key factors that have led to the rapid growth of the solar industry is the reduced cost of producing solar equipment, particularly solar panels. Over the last decade, there has been a 60 percent reduction in the cost of installing photovoltaic modules. It is interesting to note that in 2016, California controlled 34 percent of the US solar market. This is largely due to the fact that most parts of the state experience intense sunshine for the better part of the year, which makes solar energy more practical in the state. Besides, the State of California offers a wide range of incentives to promote uptake of solar power systems.
Self-sufficiency of solar power systems is usually a key concern for most people. After all, nobody wants to lose power in the middle of the night. Studies have shown that the level of sustainability of a PV system varies depending on the battery capacity. During the sunny summer months, self-sufficiency rates can range from 48-99 percent. In winter, the self-sufficiency rate drops to 30-66 percent. In 2010, photovoltaic modules were operating at 15 percent efficiency as far as converting sunlight to electrical energy goes.
Types of Batteries
Energy storage technologies used in the solar power market has relatively remained unchanged for years. There are basically two types of batteries that can be used to store energy produced by photovoltaic systems. These are lead-acid batteries and lithium-ion batteries. Knowing the pros and cons of these systems will make it easier for consumers to make an informed decision when having a solar power system installed.Lead-Acid Batteries
These are your ordinary car batteries. As the name suggests, they contain lead cells which are soaked in sulfuric acid. While they may be the most commonly used batteries, they are inefficient. They also have a short lifespan, which is measured in terms of charge-discharge cycles. Since batteries used in solar systems are charged and discharged on a daily basis, a battery with a 400-cycle rating will be used for a little bit over one year. It is important to note that lead is a heavy metal, so a decent-sized battery can be incredibly heavy. These batteries are also bulky, so they require quite a bit of space for storage. A 6 kWh lead-acid battery with 50 percent depth of discharge will have 3 kWh usable capacities.
Lithium Ion Batteries
These are the batteries used in portable consumer electronic devices, such as cell phones, laptops, tablets and the likes. They are much more efficient than lead-acid batteries. They are also small and lightweight, which makes it possible for manufacturers to build portable electronic devices. Lithium-ion batteries come with a longer life expectancy, which translates to reduced replacement costs. With these benefits, however, comes a downside. These batteries are much more expensive than your ordinary lead-acid batteries. A 6 kWh lithium-ion battery with a 75 percent depth of discharge will have a 4.5 kWh usable capacity.
The Pros and Cons of PV Solar Systems
Photovoltaic systems tap into a power source that is available in plenty. They are also emission-free and do not leave a carbon footprint. The development of more efficient batteries will lead to advancements in the renewable energy sector. That is why investment firms view the renewable energy sector as having a bright and strong future. However, there are some setbacks/shortcomings/challenges associated with solar power systems. For one, energy storage is a huge problem.
While PV power systems are able to produce enough energy to meet all our energy needs, storage is a huge problem as these systems are not able to store energy to be used on cloudy days and dark nights. Secondly, solar equipment is costly. While solar panels have become cheaper and more efficient, battery technology has not changed much. Please note that a PV system that uses battery technology would only be profitable if the battery cost $200/kWh.
Future Growth of PV Systems
The value of the battery market is estimated to rise to $250 billion by 2040. The key driver for change in the battery industry will be electric cars. We need large, utility level batteries to make renewable energy more sustainable. This presents a huge opportunity for engineers. Currently, a 100MW energy storage facility is being built in Long Beach, California. Large-scale battery storage will be gaining popularity, acceptance and usage by utility companies, such as Southern California Electric (SCE). By 2021, 1,800MW of new energy storage provided by lithium-ion batteries will be coming on line. This would equate to almost 5,900MWh of electricity stored.
Green Mountain Power (GMP), a Vermont Utility company that provides power to over 265,000 customers, has taken advantage of energy storage technologies and saved its customers over $200,000 per hour. The company is also offering batteries for lease at $37.50 per month.
The projected growth in the battery market is expected to increase the demand for engineers further. The future of efficient solar energy is dependent on energy storage. The good news is that there are dozens of companies that have invested in R&D projects that focus on improving battery technology. These projects are expected to produce efficient batteries that have a higher energy storage capacity. Top universities are also conducting a lot of research on the same subject.
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