Energy Your Way:
Onsite Options From Pacifico Power
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How Solar Works
Photovoltaic (PV), or solar systems convert light into electricity. The key component in the system is a photovoltaic. Sunlight strikes the silicon wafer knocking electrons loose which can only flow in one direction, creating electrical current. Photovoltaic modules produce energy in direct current (DC) and is typically passed through an inverter to match the alternating current (AC) used in most facilities and devices.
A fixed solar array is one that does not rotate to follow the sun throughout the day (tracking). On average, a fixed solar array produces energy for about 7 hours per day when the sun is out. However, this can vary significantly based on the season, latitude, cloud cover, angle, and the tilt of the modules. Heat and soiling also reduce production.
The energy production of solar panels is too variable to connect directly to facilities and equipment, so it typically goes straight to the grid in exchange for credits or other payment. Pairing solar with batteries and switchgear can allow for the energy to be used locally.
The Sun’s Path During
Summer and Winter
Historical Mean *LCOE Values
*Levelized Cost of Energy
The cost of solar modules has come down enough in the last 10 years that solar energy is now the cheapest form of energy. Electricity from solar energy from huge arrays in sunny locations is sold for less than $0.02 per kilowatt. The cost of a solar system is dependent largely on the system size and the mounting method – ground mount, rooftop or carport. The cost is higher for smaller commercial and industrial systems, but it is still often less than retail energy cost.
Large energy storage systems, or batteries, extend the value of intermittent energy resources such as wind and solar. Inexpensive but intermittent energy is stored when there is a surplus and released (dispatched) when the resource dips in production or when a substitute is needed for grid energy when it is most expensive.
Many battery technologies, such as redox flow, flywheel, and compressed air, exist for different use cases. But most battery storage systems currently use lithium-ion cells like those found in laptop computers. In large energy storage systems, battery cells are joined together and connected in a series with a computer, or battery management system (BMS), that controls charging and discharging. Like solar systems, a battery storage system uses inverters to convert the energy stored as direct current (DC) into the more practical alternating current (AC).
Energy System With Solar,
One cost of using a battery system is lost energy. Round-trip efficiency measures how much energy is lost during the charging, discharging, and inversion processes. Lithium-ion batteries are superior in round-trip efficiency and represent 80–90% of installed energy storage systems today
Batteries are for savings
Batteries can be used to save on energy costs when there are differences in prices based on the time of day, known as time-of-use (TOU) rates. The difference between peak (highest) and off-peak (lowest) rates can be $0.10 cents per kilowatt hour or even higher, and it’s generally greater in the summer than in the winter. The batteries can store energy when it is least expensive and dispatch the energy when it is most expensive.
Recently, utilities began dividing their energy charges into two main buckets: 1) the amount of energy used and 2) the maximum amount of energy used by the customer at any one time, known as demand. Many tariffs actually have two demand charges—one for the highest energy demand in the billing period and another for the highest energy demand during the on-peak periods in the same billing period. Demand charges can be more than 50% of a customer’s bill. Batteries are excellent at reducing demand charges. Batteries can be programmed to store energy until the user is nearing a peak point in energy consumption and release the energy at the same time so the energy drawn from the utility stays flat or even decreases. In this way, the utility would not see the customer’s demand peak, as illustrated here.
Optimization of how and when a battery charges and discharges requires sophisticated data analysis and controls. The system considers both known values (current value of energy, energy reserves available, current demand) and unknown values (future value, future demand, future production). Past energy consumption patterns help set a discharge profile, but good software controls can continue to learn from consumption and production patterns to get the most value from an energy system.
Between government incentives, reduced cost, and new smart controls, batteries now frequently pay for themselves and add additional value by shifting energy usage and reducing demand charges.
The Microgrid in Action
A microgrid is an electrical system in which the facilities and equipment are connected to the grid, but that can also be isolated from the grid and still maintain power. Although microgrids can be designed to operate indefinitely, they are more often engineered to maintain power for a matter of hours, not days.
There are three basic components of a microgrid:
- Generation – A microgrid needs a local source of power. This may be solar, wind, fuel cells or generators and is likely combined with batteries. Microgrids frequently include a dispatchable energy source, one that can be turned on or off as needed such as a diesel generator.
- Switchgear – Some infrastructure is needed to disconnect from and reconnect to the grid – known as ‘islanding’ – and to reconnect when needed.
- Controller – A proper control system knows when islanding is necessary and it sends the signals to island, initiate generation, use batteries and flip switches.
A microgrid allows the customer to be immune to disruptions in energy supply from the grid. A microgrid may also help control costs by providing predictable generation on-site and reducing the use of increasingly expensive grid energy.
Battery storage has become more relevant and useful in microgrids because of its declining cost and increased functionality and controls.
Energy is generated in direct current (DC), yet the grid and devices operate on alternating current (AC). The difference requires the energy to be converted using an inverter. Inverters take in DC energy and pass it through a switching mechanism up to 60 seconds per second, reversing polarity to create alternating power. There is loss in converting the energy, so the AC output will be approximately 80% of the DC input.
DC (to) AC
The Conversion of direct current (DC) into alternating current (AC).
The simultaneous production of electricity and steam from a single fuel source, delivering energy efficiency of up to 86%.
Onsite generation can be divided into two categories: Prime and Emergency Standby.
Prime power generators involve far more annual run hours than a pure standby application. Gas engines were designed for extended duty with lower power density and higher first cost than diesel engines. In this application fuel cost, maintenance cost, and emissions are the key concerns. Gas engines have cleaner exhaust emissions and deliver a significantly lower cost energy than diesel engines. Fast startups and rapid load acceptance are not a priority in prime power applications.
Standby generators typically operate for less than 100 hours per year, and operations can be sporadic. Diesel engines have high-power density, low first cost, and can assume loads quickly during emergency startups. Fuel cost, maintenance cost, and emissions are secondary concerns for diesel generators due to low hours of annual usage.
Choosing the right on-site generation requires an understanding of the loads to be powered, the capability required of the engine to meet the loads, the site’s access to cost-effective fuel, and the local emissions requirements.
At scale (greater than 1 MW), gas generation can be very competitive with grid power in terms of cost. Further, since the utilization may or go up or down, it is important to look at each site individually to determine the economics of placing on-site generators.
Uninterruptable Power Supply
UPS systems provide the ability to draw power from batteries while they’re being charged. These units are used to protect critical devices that cannot lose power for even a very brief time, such as a life support system or a computer server.
To understand the benefits of a UPS system, think of it as you would a water tower. First, as long as there is water in the tower, the flow will be constant. Second, the tower can be filled and used simultaneously. A UPS system operates in much the same way. All energy flows through the unit battery so any short-term disruption in supply will not impact the flow of energy.
While UPS systems are useful for preventing power disruptions, the hardware is expensive, and these systems consume 3–4% of the energy that passes through them. When a customer has little or no tolerance for voltage dips, a UPS unit is a good tool to allow an energy system to seamlessly transition to or from the grid.
The Importance of the
Uninterruptable Power Supply
Avoid Power Issues
A UPS protects against the following:
- Power Outage
- Power Surges
- Power Sags
- Over Voltage
- Under Voltage
- Line Noise
U.S. Fuel Cell Market Size,
by Application (Units)
Fuel cells use a chemical reaction to extract energy from fuel instead of using combustion. Typically fuel cells will combine oxygen, natural gas, and a catalyst at high pressure between a cathode and anode. The outputs of the process are energy, steam and carbon dioxide. A fuel cell system is best utilized running constantly as a primary source of power and can be scaled up for large usage.
Fuel cells are not considered 100% green because of their use of natural gas. The system releases carbon dioxide when using natural gas as the feedstock, but it does so at a substantially lower rate than combine cycle natural gas turbines. Also, fuel cells do not produce harmful sulfuric and nitrogen oxides (SOx, NOx) and thus are significantly cleaner than standard diesel generators and even grid energy. Fuel cells can be configured to run using hydrogen gas instead of natural gas in which case they will only release steam.
The biggest challenge for the adoption of fuel cells that run solely on hydrogen gas is the high cost of the energy necessary to create the hydrogen gas. It is an energy-intensive process to convert water to hydrogen and oxygen and then use the hydrogen to produce energy. Likewise, capturing the carbon from a natural gas process is not currently cost-effective, though innovation in this area continues.
The levelized cost of energy from fuel cells is becoming much more competitive with current retail rates charged by utilities, particularly in coastal states. In many business cases, it makes sense to consider fuel cells, particularly if facilities are using large amounts of energy at high rates.
Like a breaker box on your home, switchgear is what brings all of the technologies together. Switchgear is standard electrical equipment that contains switches, fuses and circuit breakers at the point of connection between a facility and the grid. When a new energy system is installed on a facility, upgrades to the current switchgear may be necessary. The switchgear controls parts of the electrical system and allows segments of the full system to be taken on or off-line for maintenance or to clear faults.