Is solar-thermal power generation reliable?

The key technology lies in the production and manufacturing of the condenser, as well as two aspects of control, one is the automatic tracking control, so that the trough condenser is always aligned with the sun to ensure the maximum absorption of solar energy, according to statistics, the energy obtained by tracking is 37.7% higher than that of non-tracking. The other is the temperature and pressure control of the heat transfer liquid circuit.

The temperature of the trough system after concentrating light can reach about 400°C.

3, disc photothermal power generation system

The disk system is a point focus, and the solar receiver at the focal point collects high temperature heat energy, heats the working medium, drives the generator set, or places the solar Stirling power generation device directly at the focal point. This kind of system has the characteristics of long life, high efficiency, strong flexibility, can operate independently, and is very suitable for use as a small power supply in remote areas.

The general disk solar thermal power is 10.25kW, and the diameter of the condenser is 5.10 meters.

Small disc type photothermal power generation device

By comparing the three technical routes, the tower has the greatest development potential in large-scale power generation, but the initial unit investment is too large and it is difficult to reduce the cost, and there is a lack of practical experience in the operation of large-scale power generation equipment.

Trough system structure is relatively simple, the technology is relatively mature, the commercial operation experience is rich, is still the mainstream route of the current solar thermal power generation, but its small concentrating ratio, the system operating temperature is low, the core component vacuum tube technology is not mature, the surface of the heat absorption tube selective coating performance is not stable and other problems still exist.

The disc has the highest thermal efficiency, compact structure and easy installation, which is very suitable for distributed small-scale energy systems, but the key technology of Stirling heat engine is difficult, and it is still in the experimental demonstration stage.

Comparison of three technical Routes (2013)

(3) are the use of solar energy, photovoltaic power generation and solar thermal power generation what is the difference?

The principle of photovoltaic power generation is called "photovoltaic", that is, when the sun shines on the solar cell, the battery absorbs light energy, and the abnormal charge accumulation occurs at both ends of the battery, that is, the voltage is generated, the electrode is led out and connected to the load, and the current is generated.

Photovoltaic cell power generation principle and photovoltaic power station system diagram

Therefore, in addition to the source of the sun, photovoltaic power generation and solar thermal power generation are completely different things. But the two are often compared together to see who is stronger. Let's also compare today, first look at photovoltaic power generation, the main advantages are:

(1) basically not affected by the region, theoretically as long as the solar energy can be installed;

(2) No fossil energy consumption, no pollution, zero noise;

(3) The power generation process is simple, directly from light energy to electricity, there is no intermediate link;

(4) Occupy less land, if installed on the roof, the area is basically zero;

(5) Simple structure, easy to build, low maintenance cost.

Of course, the disadvantages of photovoltaic power generation are also obvious:

(1) Cloudy days, no power output at night;

(2) Because there is no intermediate link, the cost of energy storage is high, which limits the scale of access to the grid;

(3) At present, the efficiency is still relatively low compared with thermal power, and the photovoltaic conversion efficiency is less than 20%.

Looking at solar thermal power generation, its biggest advantage is that there is an intermediate link, because there is heat as an intermediate energy source, it has three major advantages:

(1) The cost of energy storage is greatly reduced, and the maturity of thermal energy storage technology is much higher than that of electric energy storage;

(2) The resulting high schedulability of power generation, which is very similar to a thermal power station, can adjust the power generation according to the load at any time, smooth output power;

(3) Because the output can be smooth, it has the possibility of being used as a power grid rotation backup and peak filling output, which can be equivalent to "fast thermal power unit + pumped storage unit".

But the disadvantages are also obvious:

(1) Regional is hard, photothermal power generation has high working temperature requirements, and requires direct light, so it is generally built in the desert;

(2) The cost is high, the cost of solar thermal power generation is more than double the cost of conventional energy power generation, the investment cost of the power station is 4 times that of photovoltaic, the solar flow density is low, the need for a large area of optical reflectors and expensive receiving devices to directly convert solar energy into heat energy, the process of investment costs accounted for about half of the entire power station investment, This is the biggest reason for the high cost of solar thermal power generation;